1. Field of the Invention
The invention relates generally to gas meters and more particularly to a gas meter having an optical coupling to an external meter interface.
2. Description of the Prior Art
Within recent years a considerable amount of interest has been generated for remote meter reading for gas meters. In one technique, meter reading signals are transmitted from the gas meter through wires to a communication network and then through the network to the gas provider or utility company. However, a problem with this technique is that there is a possibility that electricity from a lightening strike could be carried by the wires into the gas meter and, if a gas leak was present, cause a spark that would result in an explosion. In order to solve this problem, wireless communication is sometimes used. However, the difficulty of meeting government signal regulations in some locations and cost of the wireless equipment sometimes make wireless systems uneconomical. Several workers have used or proposed using optic communication through fiber optic cables in order to avoid the possibility of a lightening induced explosion without the difficulties and cost of wireless communication. However, the known remote fiber optic gas meter reading systems are relatively complex and expensive or have the possibility that a backward flow of gas or a flash light shined into the gas meter can cause a false reading.